Yuri wrote at 2007-2-8 15:09 +0100: > I need a field in zope object which act as a sequence. I mean every >time I create an object, the value is the previous sequence value of the >last object created + 1. > > also I need to browse the objects by sequence (from the object 1 to the >last, by the sequence number) > > I think I need a catalog FieldIndex to store the sequence for searches, >a property in the object. > > Can I use the catalog to retrieve the max value of the index, so when I >create the object, I just add 1 and store it in the property?
You can -- but it is unsafe (concurrent transaction can see the same value and you may use the same id for different objects). A better alternative is to implement the sequence object directly -- as a persistent object with an integer attribute (and a method to fetch the next value). -- Dieter _______________________________________________ Zope maillist - Zope@zope.org http://mail.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope-dev )